(CNN) -- A Philadelphia, Pennsylvania, pet store expecting a shipment of exotic fish this week found itself with a man's dead body instead.
The man's widow told CNN that it might have been her husband's "last practical joke."
The body of Jon Kenoyer, a California man who suffered from Alzheimer's disease, was being donated to an Allentown, Pennsylvania, research group, Life Quest Anatomical.
The shipment was handled by US Airways, which also has delivered imported fish from throughout the world to Pets Plus Pet Center for more than a decade, store manager Mike Mullarkey said.
On Tuesday, Mullarkey said, he received what he thought was an expected shipment of seahorses, anemones and corals from Vietnam via California. Before opening it, however, he discovered that the box's label indicated that it contained the remains of a man who had died four days before.
The Pets Plus people were "shocked to see that," he said.
Mary Kenoyer, Jon Kenoyer's widow, told CNN that she was initially startled by the news, but was able to see the comic side of it.
"At first, of course, you're upset and shocked. But then I realized it was just a mistake," she said.
Noting her husband had been afraid of flying during his life, she said, "He's just playing the last practical joke on me for putting him on a plane."
Kenoyer said she hopes news of the mistake won't discourage others from donating their bodies to science. "The casket wasn't opened and was treated with respect," she said.
Mullarkey said police supervised the return of the shipment to US Airways, which rerouted it to Life Quest.
"In all the years, I can understand a mixup," Mullarkey said. "But something like that, I think, should be handled a little more delicately."
US Airways issued a statement of apology: "Regrettably, there was an unfortunate mixup yesterday at the US Airways Cargo facility near Philadelphia International Airport. The mixup occurred due to a verbal miscommunication between a delivery driver and the cargo representative. We are working to rectify the situation and are deeply sorry for the inconvenience this has caused."
A spokeswoman at Life Quest Anatomical declined to comment.